钉钉上传图片报错：40035 不合法的参数

代码如下 $upload = $this->dingtalkcurl('https://oapi.dingtalk.com/media/upload?access_token='.$token['access_token'].'&type=image', array('media'=>'@/static/admin/img/microcrm.png'));
$upload = $this->dingtalkcurl('https://oapi.dingtalk.com/media/upload?access_token='.$token['access_token'].'&type=image', array('media'=>'@./microcrm.png'));


function http_post($url,$param){
        $oCurl = curl_init();
        //下面判断https 和 http；因为钉钉接口是 Https请求
        if(stripos($url,"https://")!==FALSE){
            curl_setopt($oCurl, CURLOPT_SSL_VERIFYPEER, FALSE);
            curl_setopt($oCurl, CURLOPT_SSL_VERIFYHOST, false);
        }
        curl_setopt($oCurl, CURLOPT_URL, $url);
        curl_setopt($oCurl, CURLOPT_RETURNTRANSFER, 1 );
        curl_setopt($oCurl, CURLOPT_POST,true);
        curl_setopt($oCurl, CURLOPT_POSTFIELDS,$param);
        $sContent = curl_exec($oCurl);
        $aStatus = curl_getinfo($oCurl);
        if(intval($aStatus["http_code"])==200){
            return $sContent;
        }else{
            return false;
        }
    }


    public function dingtalkcurl($url,$data=null){
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_URL, $url);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($curl, CURLOPT_POST, 1);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($curl,CURLOPT_POSTFIELDS,$data);
        $output = curl_exec($curl);
        $data = curl_getinfo($curl);
        curl_close($curl);
        return $output;
    }
  请忽略类不全之类的错误，直接看方法，图片绝对路径能够访问到，相对路径也能访问到。两种curl方式也尝试过，都报40035的错。